/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package io.netty.handler.codec.sctp;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.sctp.SctpMessage;
import io.netty.handler.codec.CodecException;
import io.netty.handler.codec.MessageToMessageDecoder;

import java.util.List;

/**
 * A ChannelHandler which receives {@link SctpMessage}s which belong to a
 * application protocol form a specific SCTP Stream and decode it as
 * {@link ByteBuf}.
 */
public class SctpInboundByteStreamHandler
        extends MessageToMessageDecoder<SctpMessage>
{
    private final int protocolIdentifier;

    private final int streamIdentifier;

    /**
     * @param streamIdentifier accepted stream number, this should be >=0 or <=
     *        max stream number of the association.
     * @param protocolIdentifier supported application protocol.
     */
    public SctpInboundByteStreamHandler(int protocolIdentifier,
            int streamIdentifier)
    {
        this.protocolIdentifier = protocolIdentifier;
        this.streamIdentifier = streamIdentifier;
    }

    @Override
    public final boolean acceptInboundMessage(Object msg) throws Exception
    {
        if (super.acceptInboundMessage(msg))
        {
            return acceptInboundMessage((SctpMessage) msg);
        }
        return false;
    }

    protected boolean acceptInboundMessage(SctpMessage msg)
    {
        return msg.protocolIdentifier() == protocolIdentifier
                && msg.streamIdentifier() == streamIdentifier;
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, SctpMessage msg,
            List<Object> out) throws Exception
    {
        if (!msg.isComplete())
        {
            throw new CodecException(String.format(
                    "Received SctpMessage is not complete, please add %s in the "
                            + "pipeline before this handler",
                    SctpMessageCompletionHandler.class.getSimpleName()));
        }
        out.add(msg.content().retain());
    }
}
